AQA A Level Biology Paper 2 2018

1.1) Heat stress decreases the light-dependent reaction of photosynthesis. Explain why this leads to a decrease in the light-independent reaction - CORRECT ANSWER-- Less ATP - Less reduced NADP 1.2) Another effect of heat stress is a decrease in the activity of the enzyme rubisco. A decrease in the activity of an enzyme means that the rate of the reaction it catalyses becomes slower. A decrease in the activity of the enzyme rubisco would limit the rate of photosynthesis. Explain why. - CORRECT ANSWER-- Less CO2 react with RuBP - Less GP 1.3) Where precisely is rubisco found in a cell? - CORRECT ANSWER-Stroma 1.4) The scientists concluded that heat stress reduces the activity of rubisco in plant leaves by affecting rubisco activase. Use all the information to evaluate their conclusion. - CORRECT ANSWER-1. Rubisco activity increases with temperature. 2. Rubisco activase activity decreases at high temperatures. 3. Results/graphs suggest activase cannot/does not affect activity of rubisco. 4. Results are only for cotton. 5. (Results are) for isolated enzymes. 6. No stats test. 2.1) Put a tick in the box next to the statement which describes incorrectly the effect of the mutation in an exon of a gene. - CORRECT ANSWER-Box 2. An inversion will result in a change in the number of DNA bases. 2.2) Describe how alterations to tumour suppressor genes can lead to the development of tumours. - CORRECT ANSWER-1.(Increased) methylation (of tumour suppressor genes). 2.Mutation (in tumour suppressor genes). 3. Tumour suppressor genes are not transcribed/expressed 2.3) A type of malignant tumour cell divides every 8 hours. box Starting with one of these cells, how many tumour cells will be present after 4 weeks? Assume none of these cells will die. Give your answer in standard form. - CORRECT ANSWER-1.93 x 10^25 3.1) Suggest one reason why it was important that the student left the apparatus for one hour after the yeast culture reached a constant temperature. - CORRECT ANSWER-So the oxygen is used. 3.2) During her investigation, the coloured liquid moved to the right. box Explain why it moved to the right. - CORRECT ANSWER-1. Anaerobic respiration produces carbon d